1. Field of the Invention
The present invention relates to a technique for transferring data between a plurality of devices and memory in an electronic apparatus.
2. Description of the Background Art
Electronic apparatuses, such as digital still cameras, are equipped with a plurality of processing units (devices) that apply various processes to image data and the like. The operation of such an electronic apparatus proceeds as these devices process data while sequentially transferring the data between memory and themselves.
In such an electronic apparatus, each device is equipped with a buffer or buffers for temporarily storing the data transferred between the devices and memory. When data is transferred between a device and the memory, the data is once accumulated in a buffer of the device, and the accumulated data is sequentially sent to the destination. Data is thus transferred in succession without a break.
However, in conventional electronic apparatuses, the devices are previously assigned an order of priorities of data transfer. When some devices present requests for data transfer at the same time, the devices are allowed to transfer data according to the order of priorities.
Accordingly, in such conventional electronic apparatuses, devices having lower priorities are less likely to be allowed to transfer data, while devices having higher priorities can always preferentially transfer data. Therefore, the buffers in the lower-priority devices may become completely empty of data or filled up with data, which may force the devices to stop their operations.